A genetic algorithm to determine production schedule in an imperfect manufacturing system with time-vary unit cost

Considering time-vary in unit cost and imperfect quality in process, this study presents a genetic algorithm to deal with the production schedule and batch lot problem for a manufacturing system. Incorporating linearly and exponentially continuous unit production cost, we assume that defective items are reworked at a constant rate after regular production immediately. Not all of the defective items are reworked but a portion of them are scraped due to serious damage. Our objective is to minimize the expected value of total cost for this production system. A genetic algorithm with the chromosome of real number type to solve this problem is proposed. Standard GA operators are used to generate new populations. These populations are evaluated by a fitness' function using the total cost of production scheme. An explicit procedure for obtaining an approximate solution is provided.